Flood Watches in Place in Advance of Statewide Rain

April 14, 2014

The National Weather Service Forecast Offices in Gray and Caribou, Maine have posted Flood Watches across the entire State through Wednesday night. Warm temperatures and a rainstorm expected Tuesday into Wednesday have elevated flood risk in all areas. Flood potential was already high due to an above normal snowpack, river ice and rising spring stream flows.

The River Flow Advisory Commission hosted a conference call today that included information sharing by the USGS, Maine Geological Survey, river basin managers and the National Weather Service. State, County and local emergency managers and State Emergency Response Team were participants in the call.

While forecasts are still being developed, minor to moderate flooding on rivers such as the Kennebec appears possible, ice jam flooding potential is a concern in the north and small river and stream flooding is possible in all areas. Those in flood-prone areas should monitor local conditions and weather forecasts closely over the next 48 hours.

According to the National Weather Service in Gray (serving southern and western Maine), the combination of rapid snow melt and rainfall will keep rivers running high through mid-week. There is also a threat of ice jam flooding in the mountains; ice has been moving on the Carrabassett and Sandy Rivers. Rainfall is expected to be 1 to 2 inches, with the most falling in the upslope areas of the western Maine mountains.

NWS Caribou (serving northern and eastern Maine) reports that snow melt and rising river levels today could cause ice to move and possibly jam. The moderate to heavy rain Tuesday will keep river levels and the threat of ice jam flooding high through Wednesday. Ice in the northern rivers is still quite thick and strong, increasing the risk of ice jams as the rivers rise and the ice moves. Warm temperatures are creating runoff in those areas as well, and NWS Caribou reports known ice jam locations on several rivers are being monitored closely.

According to the Maine Geological Survey (Department of Agriculture, Conservation and Forestry) last week's Cooperative Snow Survey showed the snowpack water content in all of Maine to be well above normal for the time of year. Some of that water content has likely run off over the last week, but what is left will likely have become more dense, and more likely to be released with rain. Snow survey crews are in the field across the state today through Wednesday.

The USGS reported that stream flows are already high due to warm temperatures, snowmelt and runoff over the last few days. While the rivers in the south are largely free of ice, more northern tributaries are still releasing ice, and northern rivers such as the St. John still had significant ice in place.

Maine's river basin managers report that headwater storage areas have adequate storage to accommodate the rain and runoff that is expected in their areas. However, a large percentage of the drainage areas for Maine's major rivers is "unregulated", meaning small rivers and streams drain directly into a larger river, not into a storage area.

Rain is expected to overspread the State starting on Tuesday morning and moving west to east. Monday's above normal temperatures will carry into Tuesday, but colder temperatures will come in behind the storm. In fact, the "back end" of the storm may bring a small amount of wet snow. Cooler temperatures through the rest of the week will moderate the runoff once this event has ended.

In central and southern locations, runoff and increased stream flows will be seen on Tuesday in smaller rivers and streams, but Maine's larger rivers will rise and crest on Wednesday.

With the information distributed previously and shared on today's call, county and local emergency managers will be activating local plans to prepare for any flooding that does occur.

NWS Forecast offices will continue to keep emergency managers and the public advised of the flood threat throughout the event.

Safety = Stay away from flooded areas:

Flooding in the number one killer among natural disasters in the United States. More than half of deaths from flooding are vehicle-related.

A mere six inches of fast-moving flood water can knock over an adult. It takes only two feet of rushing water to carry away most vehicles. This includes pickups and SUVs.

Ice jam flooding cannot be forecast. Signs include ice piling up and appearing to block the channel, coupled with rising water levels behind the jam. Report any suspected ice jams to local officials, County Emergency Management Agency or the National Weather Service.

Stay well away from high-flowing rivers, streams and even large drainage ditches. Keep children and pets away from these areas.

Respect all barricades restricting access to flooded areas

If you encounter an unmarked flooded road, find another way around, and report the flooding to local authorities.